RE: index on null column

From: Jamadagni, Rajendra <Rajendra.Jamadagni_at_espn.com>
Date: Fri, 28 Mar 2003 05:08:36 -0800
Message-ID: <F001.005751CB.20030328050836@fatcity.com>

Here is an idea ...

Create a function that returns NULL if the value is null or any other acceptable value that can be ignored. And the function should return valid values otherwise. Then create a function based index on this and see if that helps you.

To put in other words, you are merely indexing a subset of rows that match your criteria, while ignoring others that you don't want to deal with.

Raj

---

Rajendra dot Jamadagni at espn dot com
Any views expressed here are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !!

-----Original Message-----
Sent: Thursday, March 27, 2003 9:34 PM
To: Multiple recipients of list ORACLE-L

AK

   Yes, it will benefit the non-null records. Just remember that the null values aren't indexes.

Dennis Williams
DBA, 40%OCP, 100% DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Thursday, March 27, 2003 5:19 PM
To: Multiple recipients of list ORACLE-L

I have a table with column A. there are 1000000 records in table out of which 500o records has not null in column A rest are null. if i created an index on A, will it benefit .  

thanks,
ak

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Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM

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Author: Jamadagni, Rajendra
  INET: Rajendra.Jamadagni_at_espn.com

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To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). Received on Fri Mar 28 2003 - 07:08:36 CST